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At least 325 records · Page 18Linked to original sources
PubMed1992

Alternative management of a crown root fractured tooth in a child.

A crown root fracture of a tooth in a young person may necessitate the removal of the root and the placement of a space-maintaining partial denture followed by provision of a bridge. A case is reported of an alternative approach to treatment, in which the root fragment is retained in situ until the end of the pubertal growth spurt, in order to preserve alveolar bone, following which it is removed and replaced by an implant.

Child↗
PubMed2007

Concrescence of teeth: cemental union between the crown of an impacted tooth and the roots of an erupted tooth.

Concrescence of teeth is a condition showing a union of adjacent teeth by only cementum. In all the previously reported cases, the union has been observed between the roots of the affected teeth. Here, we describe the first case that showed a concrescence of the crown of an impacted tooth and the roots of the erupted tooth. In addition, we discuss how this condition, especially the deposition of acellular cementum on the crown, occurred.

Female↗
PubMed2005

Panoramic radiographic findings as predictors of inferior alveolar nerve exposure following third molar extraction.

OBJECTIVES: The aim of this study was to estimate the sensitivity and specificity of panoramic radiographic findings in relation to inferior alveolar nerve (IAN) exposure after mandibular third molar (M3) extraction. METHODS: The study used a retrospective cohort model. The primary predictor variable was the presence or absence of > or = 1 panoramic radiographic sign associated with an increased risk for IAN injury. The secondary predictor variable was the surgeons assessment of IAN exposure risk. The outcome variable was IAN exposure, defined as direct visualization of the IAN at the time of M3 extraction. Appropriate univariate and bivariate statistics were computed and the level of statistical significance was set at P < or = .05. RESULTS: The sample was composed of 230 patients having 423 mandibular M3s evaluated and removed. Following M3 extraction, the IAN was visualized in 24 (5.7%) extraction sites. Four of the radiographic signs were statistically associated with IAN exposure ( P < or = .05). The sensitivities and specificities of the 4 radiographic findings ranged from 0.42 to 0.75 and 0.66 to 0.91. The clinicians preoperative estimate of the likelihood of IAN exposure was statistically associated with IAN exposure after M3 extraction ( P < .001; sensitivity = 0.79; specificity = 0.86). CONCLUSION: Four radiographic findings (darkening of the tooth root, narrowing of the tooth root, interruption of the white lines, and diversion of the canal) were statistically associated with IAN exposure following M3 extraction. The surgeons overall estimate of risk based on the panoramic radiograph was also statistically associated with an increased risk of IAN exposure.

Adult↗
PubMed1986

Radiographic study of alveolar bone height related to tooth and root length.

In radiographs from 76 randomly selected periodontally healthy subjects, aged 18-22 yr, at the School of Dentistry in Stockholm, the alveolar bone height was evaluated and correlated to the root length as well as to the entire tooth length. The root lengths were also related to the entire tooth lengths. The mean tooth length was found to be 24.9 mm and the mean root length 65.7% of the mean tooth length. The correlation of alveolar bone height to the root length varied between 91.5% and 96.3% and the correlation to the entire tooth length between 54.0 and 65.7%.

Adolescent↗
PubMed2002

Caiman periodontium as an intermediate between basal vertebrate ankylosis-type attachment and mammalian "true" periodontium.

The teeth of many fish, amphibia, and reptiles are attached to the alveolar bone via ankylosis. In contrast, mammalian periodontia are characterized by a gomphosis, an attachment of the tooth root in the alveolar bone socket via periodontal ligament fibers. Among the reptiles, the crocodilians are the only group featuring a gomphosis-type connection between tooth root and alveolar bone, while in other reptiles tooth-root and jawbone are connected via ankylosis. The purpose of the present study was to compare several key features of the crocodilian periodontium with those of the mammalian and noncrocodilian reptile periodontium. As experimental models for our study we chose the periodontium of newborn geckos (Hemidacylus turcicus), juvenile caimans (Caiman crocodilus crocodilus), and 10-day-postnatal Swiss-Webster mice (Mus musculus) as representative models for noncrocodilian reptiles, crocodilian reptiles, and mammals. The caiman periodontium emerged as an intermediary between the mineral-free mouse ligament and the mineralized gecko ankylosis-type attachment. Caiman ligament fibers were less organized than mouse ligament fibers but featured distinct fasciae surrounding ligament fiber bundles. Caiman Hertwig's epithelial root sheath (HERS) was similarly perforated as mouse HERS and distinctly different from the continuous gecko HERS. Both caiman and mouse HERS covered the entire tooth root length, while in the gecko HERS was limited to the coronal portion of the root, allowing for cementoid-mediated ankylosis at the apical tip of the root. We interpret our data to indicate distinct differences in mineral distribution, periodontal ligament fiber organization, and HERS distribution between noncrocodilian reptiles, crocodilian reptiles, and mammals. Mineral deposits in the caiman ligament may reflect an evolutionary position of the caiman periodontium between ankylosis and gomphosis.

Alligators and Crocodiles↗
PubMed2006

[Problems and possibility of resin abutment construction with a combined use of fiber posts: at the beginning of discussion].

When using post materials that are more rigid than teeth for abutment construction, tooth root fracture may be caused by stress concentration in the remaining part of the tooth root. Most of the tooth root fractures clinically observed in metal post abutment cases are longitudinal fractures, resulting in tooth extraction in many cases. In cases with sufficient coronal tooth substance, post-less abutment construction has recently been considered. Fiber posts have recently attracted attention as a post material for resin abutment construction due to their flexibility with elastic modulus similar to that of dentine. In Japan, although approval by the Ministry of Health, Labour and Welfare has recently been obtained, there have been few experimental studies and clinical reports on fiber posts. In this study, we performed a break-down test and finite element analysis of fiber posts as in vitro studies, and reviewed overseas references on clinical results. Experimental results show that, the effects on preventing stress concentration are high in all abutment construction methods when sufficient ferrule in the remaining teeth is present, and stress may be concentrated in the cervical area in fiber post abutment cases. Clinical results obtained from references showed that, fiber posts are superior to cast posts and commercially available metal posts, in terms of fracture and dislodgment. However, since issues were revealed in previous clinical studies, further comparison studies are necessary to evaluate the superiority of fiber posts compared with metal posts.

Dental Abutments↗
PubMed2005

Sexual dimorphism in modern human permanent teeth.

On average, males possess larger tooth crowns than females in contemporary human populations, although the degree of dimorphism varies within different populations. In previous studies, different amounts of either enamel or dentine were implicated as the cause of this dimorphism. In this study, we attempt to determine the nature of sexual dimorphism in the crowns of permanent modern human teeth and to determine if two contrasting tooth types (permanent third molars and canines) show identical patterns of dimorphism in enamel and dentine distribution. We estimated the relative contributions of both enamel and dentine to total crown size, from buccolingual sections of teeth. Our sample consisted of a total of 144 mandibular permanent third molars and 25 permanent mandibular canines of known sex. We show that sexual dimorphism is likely due, in part, to the presence of relatively more dentine in the crowns of male teeth. However, whatever the underlying cause, dimorphism in both tooth root and tooth crown size should produce measurable dimorphism in tooth weight, though this has not been previously explored. Therefore, we provide some preliminary data that indicate the usefulness of wet tooth weight as a measure of sexual dimorphism. Both male permanent third molars and canines are significantly heavier than those of females. The weight dimorphism reported here for both classes of teeth may prove a useful finding for future forensic studies. In particular, weights of canines may be more useful as a means of sexing modern human skeletal material than linear or area measurements of teeth.

Anthropology, Physical↗
PubMed1998

Drill Free Screws: a new form of osteosynthesis screw.

Although the application of self-tapping and non self-tapping screws is virtually universal in cranio-maxillofacial surgery, the inevitable, time consuming procedure of drilling a pilot hole has some potential disadvantages, such as damage to nerves, tooth roots or tooth germs, thermal necrosis of the bone and drill bit breakage. Drill Free Screws (DFS) are a recently developed type of osteosynthesis screws, having a tip like a cork screw and specially formed cutting flutes which enable insertion of the screws without drilling. DFS 1.5 and 2 mm were inserted into discs of wood, polyvinylchloride (PVC) and porcine mandibular bone of varying thicknesses between 2 and 4 mm. The values of insertion torque and maximum torque were recorded using an electric torque tester. Thereafter, the screws were inserted with a fixed torque and uniaxial pull out tests were performed. In comparison with this, the same procedure was performed using 1.5 and 2 mm self-tapping titanium screws. Ten trials for each screw-material-combination were conducted to determine insertion torque, maximum torque and pull out analysis. The results showed that the holding power of DFS lay between 70 and 104% of the holding power of self-tapping titanium screws; only in PVC was the difference more than 15%.

Animals↗
PubMed1984

The pathogenesis of excessive wear in the deciduous teeth of sheep.

The teeth and various supporting and ancillary tissues were examined post mortem from two flocks of sheep, one of which had previously shown high deciduous incisor wear. Sheep were killed in groups selected on clinical signs at equivalent ages from birth to 116 weeks of age. At the end of this time the lengths of clinical crowns of the remaining deciduous incisor teeth in the high wear flock were not measurable, whereas the other flock had up to 5.5 mm in visible crown. Using the cingulum as a marker, measurements were made from extracted teeth of the attrition of the crown and size of the root. The tooth root did not grow substantially longer after the 13th week of the sheep;s life. Wear facets were just visible in some sheep at six weeks. More rapid wear occurred three times in the high wear flock. The first of these was relatively small and occurred between the 13th and 27th week of age in I1 and I2. The second was larger and occurred between the 38th and 57th week of age in the winter/spring period. A third period of wear, which was not measured from the cingulum, because this structure had by then been worn away, was seen in the remaining deciduous teeth between the ages of 91 and 110 weeks of age, i.e., during the second winter and spring. In the low wear flock the first of these periods of wear did not occur, the second was of shorter duration and smaller size, and the third equivocal. Eruption of the teeth after the 6th week was principally passive. There was no difference in the degree of wear of the molar teeth from the two flocks. Histological examination showed that the wear was compensated for by the deposition of reparative dentine in the pulp cavity. This usually gave the appearance of an ordered process. However, when wear was excessively rapid, a different, less orderly form of reparative dentine was laid down. In a few cases the reparative process was not fast enough, and a connection developed between the mouth and the pulp causing pulpitis. There was no histological evidence that the supportive tissues of the teeth, or the upper dental pad, contributed to the excessive wear.

Journal Article↗
PubMedDate not supplied

[Using Lamendin and Meindl-Lovejoy methods for age at death estimation of the unknown person].

The paper presents the precise description of two methods used for age estimation on the base of single rooted tooth and cranial suture obliteration. Using the methods mentioned above, the age at death of the unknown person was estimated. A comparison of the estimated age and chronological age derived after identification, showed high usefulness of the mentioned methods.

Age Determination by Skeleton↗
PubMed1991

Effects of phosphoprotein moieties on the remineralization of human root caries.

The noncollagenous proteins, especially phosphoprotein, have been shown to modulate biomineralization. The objective of this study was to investigate the remineralization potential of human tooth root organic matrices which did or did not contain soluble non-collagenous proteins including phosphoprotein. Human tooth roots were completely demineralized using conditions that either removed or did not remove soluble phosphoprotein and were then subjected to remineralization conditions. Removal of soluble phosphoprotein resulted in remineralization while no remineralization occurred in tooth roots that still contained soluble phosphoprotein. Transmission electron microscopy and microradiography demonstrated that demineralized cementum did not remineralize under any of the conditions used in this study. Collagenase digestion of demineralized and salt-reextracted tooth root organic matrices revealed that a nonsoluble phosphoprotein was present in the matrices. Amino acid analysis and SDS-PAGE showed that this nonsoluble phosphoprotein was similar in composition to the soluble phosphoprotein. This work suggests that the removal of soluble, noncollagenous proteins, especially phosphoprotein from root caries lesions, may enhance their remineralization potential.

Amino Acids↗